What you described is not exactly a panic attack but it's close. It would become one if you felt that you lost control over your heart rate. Let's say you re HR is 100 on clen.
If you get a panick attack it would jump to 150 and over. Then you would say to yourself "damn my heart rate is so high,,my BP is so high too, I'm gonna have a heart attack". Then you would become more and more anxious because of that thought and your heart would pump harder and harder. It's a vicious cycle and it may actually be dangerous, as least I think so.